The present invention relates to concentric electrical connectors and, particularly, to the type of connector commonly known as a “phone plug” that is commonly used to connect musical instruments to amplifiers or other such equipment.
The dimensions of such plugs and associated jacks have been set according to JIS (Japan Industry Standard) whereby manufacturers of various components will be sure of interchangeability and connectivity by purchasers of components from various sources. Notwithstanding such standards, the ¼ inch diameter male phone plugs and jacks do not always mate as specified. In particular, whereas most commercially available male plugs conform closely to the standard specification, many female jacks (receptacles) are quite far out of specification. The inside of a jack usually includes some form of spring contact that is designed to contact a detent in the tip of the male plug. When the spring contact is either too short or too long in length, poor electrical contact with the plug tip degrades the musician's performance. This condition can cause the plug to have minimal retention of the plug to the jack, and in some cases the spring contact can actually push the plug out of the jack, causing total loss of electrical connection.